Steam boiler regulating system



y 1947- J. LOUMIET ET LAVIGNE 2, 23,397

STEAM BOILER REGULATING SYSTEM Filed Oct. 8, 1941 4 Sheets-Sheet lllllll| t g f7q./.

C/ i b m T D I INVENTOR Jean Loam/er ef Lav/qne BY WM ATTORNEY 5 y 947.J. LOUMIET ET LAVIGNE 2,423,397

I STEAM BOILER REGULATING SYSTEM Filed Oct. 8, 1941 4 Sheets-Sheet 2INVENTOB. Jean Loum'e/e/Lawqne July 1, 1947;

J. LOUMIET ET LAVIGNE STEAM BOILERREGUDATING SYSTEM Filed Oct. 8, 1941 4Sheets-Sheet 3 mvsmon Jean Loam/er er Lav/gne BY ATTORNEY 5 4 J. EOUMIETET LAVIGNE STEAM BOXLER REGULATING SYSTEM Filed 061.. 8, 1941 4Sheets-Sheet 4 INVENTQR. Jean Loam/er e/Lawqne M *QQZZL -AT1'0R NEY .S

Patented July 1, 1941 STEAM BOILER REGULATING SYSTEM Jean Loumiet etLavigne, Itabo, Cuba Application October 8, 1941, Serial No. 414,052

' In Cuba October 17, 1940 '11 Claims; (Cl. 122-448) This inventionrelates to improvements in the regulation of steam boiler systems and inparticular is based on the steam boiler regulating systems disclosed inmy U. S. Patents No. 2,338,773 and No. 2,377,254. The latter applica--tion correlates various features of the former application to obtaintotal automatic regulation of the steam boiler system, and specificallythe regulation of the feed water as well as of the means of combustion,namely, fuel and air. While the invention is described in itsapplication to steam generating systems having a water chamber, it maybe applied to boiler systems having no water chamber, as by replacing asystem in which the regulation is governed by variations in water levelby one in which the regulation is governed by differences in thetemperature of the superheated steam.

making or breaking contact with an electrode appropriately located influids rise and fall.

A second feature of said application consists in making the feed of themeans of combustion interdependent with the water feed, and providing acomplementary regulation of the feed of the means of combustion toadjust it accurately to the needs of the boiler system. A third featureof said application eliminates oscillations in the automatic water feedregulation.

The second application discloses an arrangement combining features ofthe first application for complete regulation of boiler systems, adaptedto satisfy the two conditions for efficient functioning of the boilersystem, namely, maintenance of a constant water level and maintenance ofconstant steam pressure.

The present invention introduces a number of improvements in thedisclosure of said prior applications. One feature is the utilizatlonofa horizontal column of mercury located between vertical columns of ailuid that is a poor electrical conductor. By utilizing a capillaryhorizontal tube, which may have a diameter for instance of less thanthreemillimeters, the merthe fluid passage as the generators.

utilizing variations movements may be cury column fllls the tube and isprevented from escaping. The location of the mercury column thereforewill correspond boiler water level; but in view of the very smalldiameter of the mercury column it amplifies greatly the variations insaid water level. The mercury therefore can be employed as an indicatorand for governing the feed regulating system.

The feed control by means of the horizontal mercury column may utilizethe systems disclosed in said applications. A specific improvementhowever is the utilization of double electrodes arranged so that thecontrol circuit is closed by bridging the gap between the electrodes,instead of maintaining a constant connection with the mercury column.This reduces the path of the current through the mercury or otherconducting liquid, an important feature where liquids of lowerconductivity, such as saline solutions, are used.

Another feature is trodes by enclosing the conducting column, such asmercury, in a tube made of a material of lower conductivity, such as ina current through the tube caused by shifting of the mercury column tocontrol the feed. Since various known electrical systems of regulationcan be utilized with this arrangement, they will not be described. Thisarrangement permits the utilization of a jointless tube, an advantagewith high pressure steam This feature may utilize an electromagnet whosearmature will be shifted proportionately to variations in the currentand therefore in the boiler water level; and the armature directlytransmitted to the valve regulating the feed.

An important feature of this invention is the elimination ofoscillations in the adjustment of the water level in accordance with thefirst feature of the first patent application mentioned above. Thisoscillation is due to the fact that when the water level falls, forinstance, the feed water valve is slowly opened until the water levelceases to fall, which indicates full correction of the feed deficiency.However, the opening motion of the valve continues while the water isrising until it reaches the normal level; and therefore the valve isnecessarily opened in excess of the requirements for correction.Consequently, the water will rise abOV the normal level and theoperation will be repeated in reverse, producing oscillation of thewater level.

The third feature of said first patent application to the position ofthe the elimination of the 'elec-' high resistance steel, andeliminatessuch oscillations to a certain extent; but an important feature of thisinvention is to accomplish this purpose in a still more eifectivemanner, substantially preventing such oscillations This is in generalaccomplished by providing an arrangement which will actuate the valveonly when the eiectromagnet armature or other controlling element ismoving away from normal position, arresting such actuation when it ismoving toward normal position. 'lhls will serve to arrest the valve whenthe motion of the water level away from normal is arrested, though thevalve will normally overrun this position slightly and thereby start thewater level back toward normal position. The consequent return movementof the electromagnet armature or the like will disconnect the motoroperating the valve. Consequently, whether the water level rises orfalls from normal position, as is the case where there is a variation insteam consumption, the valve aperture proper for providing the feedcorresponding to the new steam consumption is obtained in a singleoperation without material oscillation.

Several arrangements of this type can be employed. In the form disclosedan appendage connected to the armature contacts a movable member shiftedby outward movement of the armature, the valve operating current passingthrough the contact; but when the motion of the armature is reversed andit returns toward the center of its path the contact between thearmature and said member is broken, arresting the valve adjustment. Thearmature may return said member to normal position mechanically, but thecontact necessary for this purpose is insulated. Separate elements maybe employed which are Operative during the rise and fall respectively ofthe water level from normal position.

This mechanical principle may be embodied in various constructions.Moreover, this system of control can b applied to any regulating systemoperated by variations in the intensity of an electric current. It maybe employed in connection with the variable resistance constructionutilizing a shifting column of conducting liquid in a high resistancetube as indicated above. It is likewise applicable to the multipleliquid column systems disclosed in said applications.

A metallic filament extending lengthwise through an end of theconducting column may be utilized; but an arrangement of this type isnot especially sensitive. To increase its sensitivity, the metallicfilament may be replaced by a carbon filament in a glass support.

One factor which must be considered in connection with the utilizationof the features of this invention in order to maintain constant boilerpressure is the fact that a fall in steam pressure and temperatureresults in the transfer of heat from the boiler, masonry and othercontiguous parts of the system into the steam; whereas an increase inthe temperature of the steam requires an additional amount of heat tocompensate for the heat transmitted to such masonry and boiler to bringup their temperature. These factors are not reflected in the manometerreading: but they must be taken into account.

This is in general accomplished by providing an arrangement forcontinuing the corrective movement of the valve controlling the feed ofmeans of combustion for the appropriate period after it has reach'ed theproper opening and the position. This result consideration the boilervaries when 4 move back toward normal is advantageously obtained byproviding a small spring at the point of contact between the armaturetact member, arranged to tween the armature and said member for acertain period after the armature has started to move away from saidmember, the contact continuing until the spring is relieved of itscompression. The spring can of course be mounted either on the armatureor its connections, or on the movable contact member.

Another feature is the provision of an arrangement for correcting theresulting deviation in the feed of means of combustion from the correctnormal supply after sumcient excess h'eat has been generated tocompensate for absorption thereof by the elements surrounding the steamchamber and passage. For this purpose an arrangement is provided bywhich the control motor, after having been arrested, is again started inthe reverse direction and is operated during a period which issuiilcient to eliminate the feed deviation from normal. One arrangementof this type is described; but this is intended to be by way ofillustration and not limitation, since other arrangements may beutilized.

These features may be applied to th automatic feed either of the wateror of the means of combustion but when both feeds are relulated withoutinterconnection, they interfere with each other, since a variation inone feed changes the conditions affecting the other feed. The secondfeature 0! my first application, as well as my second application abovementioned, diminish these difficulties; but it is necessary to take intofact that the efliciency of the the steam consumption varies; andtherefore the required quantity of the means of combustion for turning aiven quantity of water into steam will vary. For instance, if the systemis in equilibrium, a sudden increase in steam consumption will producean immediate fall in pressure as well as in water level, the pressuredrop operating to increase all of the feeds while the water level droptends to increas the water feed relative to the feed of the means ofcombustion. This produces a defect in regulation which will result inoscillations and delays in returning to equilibrium.

If under similar circumstances the water level is utilized to controlboth feeds, this dimoulty will not arise. However, the adjustment of thetwo feeds is not necessarily simultaneou in practice. I1 regulation ofthe feed of the means of combustion is obtained before that of the waterfeed, the regulation will be thrown out of equilibrium, requiring anincrease in the feed of the means of combustion, which may be obtainedby providing the additional time increment above described. If on thecontrary, the regulation of the water feed is obtained before that ofthe feed of the means of'combustion, the resulting lack of equilibriumis compensated by the necessity for additional heat absorbed by theboiler and other steam contacting parts as normal pressure is regained.Consequently, the latter arrangement is preferable for rapid adjustment.In steam generating systems of the Benson type in which there is noboiler, the. main regulation must obviously be effected by steampressure variations.

.Another feature of the invention is the provision of anauxiliaryregulation which will accelerate the return of the steam pressure tonormal providing. increased sensitivity and, if nec- I-rmaturestartstoessary, increased amplitude, regulation may replace the main regulationto maintain the pressure constant while the latter regulation isreaching its ultimate status.

The auxiliary regulation, eflected through temperature variations in thesuperheated steam and arranged to maintain such temperature constant,serves to increase the proportion of the means oi combustion in relationto the water teed when the main regulation increases both feeds. Suchauxiliary regulation utilizes the current from an electric pyrometer orthe like, heated by the superheated steam.

In the accompanying drawings, I

Fig. l is a vertical section of a system embodying the invention,operaterLby variations in the boiler water level to maintain said levelconstant; 7

Fig. 2 is a plan view thereof;

Fig. 8 is a vertical section through amodiflcation, applied to the waterfeed line;

Fig. 4 is a similar view of another form operated by boiler pressurevariations to maintain such pressure constant, applied to the fluid tuelteed;

Fig. 5 'is a similar view of a system operated by boiler pressurevariations for preventing oscillations in the feed regulation;

Fig.8isa detail 01 Fig. 5;

Fig. '7 is a similar view or another arrangement for suppressingoscillations in the automatic regulation of the water feed, operated byvariations in the boiler water level; and Fig. 8 i an elevation 0!another type oi'construction for suppressing oscillations in theregulating systems.

Referring to Figs. 1

illustrated therein is actuated by variations in boiler water level andis advantageously applicable to automatic regulation of the water feed.

In the vertical columns comprised in that apparatus, starting from itsconnection with the steam chamber of the boiler through the valve V1, onto its connection-with the water chamber of the same boiler through thevalve Vz, the column A is made up of condensed water. The upper part ofsaid column is constantly kept up through steam condensations in tube L,the excess of water being continuously emptied into the boiler; and anincrease of section at N prevents a sudden motion of the fluid columnsof the apparatus from causing an appreciable variation in the level orthe aforesaid column. The column B is formed at its lower part by thecondensed water column forming part of column A, and at its upper partby oil.

The horizontal column E is located in a tube of less than 3 millimetersin diameter filled ith mercury at its central part, and -filled at itsleft hand part with oil from column B with which it connects throughchamber D. In the same way, the right hand part of the horizonta1 columnE is filled with oil from column G with which it connects throughchamber F. Column G is formed by oil at the upper part, and at the lowerpart by a water solution of salt. Column H is almost totally formed bythe same dense liquid occupying the lower part of column G, exceptingits upper part which is formed by oil. Finally, column J is formed atits upper part by the same oil as column H with which it connects, andat its lower part by water from the, boiler with which it also connectsthrough horizontal tube K and valve V: mentioned above.

In said variable level apparatus the difference so that the latter and2, the embodiment relatively dense liquid, for example, a

- of pressure between the steam chamber and the water chamber ofthe'boiler, is balanced by the diflerences in densities of the fluids oithe several columns, so placed that the tendency to motion of the fluidin those columns from V1 to V2. which would exist it all the fluids wereof the same density, 'is checked by the fact that the columns that tendto rise in such motion are made up in greater part oi dense liquids;while the columns tending to descend are, on the contrary, made up ingreater part of light fluids.

when the height of the water in the boiler changes, the equilibrium isdestroyed. It, for example, we suppose that the level'descends, thefluids of the column have a tendency to move from V; toward V2; but thenthe quantity or the dense fluids .increases in the columns that areraised by that motion, and the quantity of such dense fluids, on thecontrary, diminishes in the columns tending to descend, because they arereplaced by light fluids. Hence, a new equilibrium is rapidlyestablished with a new position of the successive fluids of the columns.

Those variations in position are transmitted to the horizontal column ofmercury which, by reason of such variations, is displaced in thehorizontal tube E to one side or the other. The variations in positionof the mercury column considerably amplify the variations in thepositions of the fluids of the vertical columns, in accordance with theproportions between the section of the first one and that of the secondones of those columns. In consequence, the variable level apparatus canbe made extremely sensitive, provided tube E be made long enough.

The regulation illustrated by Figure 1 applies the first arrangementdisclosed in my flrst above mentioned patent application, with thedifference of a simpler electrical arrangement. In this figure When, byreason of a decrease in boiler pressure, motion of the fluids in theapparatus is produced and the mercury column is placed in contact witha, it is a sign that the water has a tendency to descendfrom its normallevel and, in consequence, its feed is deficient. The coil am then comesinto action and closes switches or, a: and as. The current from line 2,which'was broken, is reestablished through switch or, and provides acircuit for the electric current which, entering by line I, runs throughthe circuits of the motor which is supposed to be of alternating currenttype. At the same time, the line i has been placed in contact with line4 through the switch as, and the line 2 has been placed in contact withline 3 through the switch as.

'The starting current enters then the motor through line 4, going outthrough line 3, which produces motion of that motor in the directionproper for slowly increasing the aperture of the valve governing thewater feed. When, by reason of such increase in feed, the lowering ofthe water in the boiler is checked and its level rises again, the motionof the fluids in the vertical columns of the regulating apparatus takeplace in the amass? inverse direction and the mercury column reversesits motion, moving from a toward b.

When, by reason of that motion, the contact of that column with theelectrode a ceases, the coil am is deenergized, the switches a1, a: anda: open and the current that drives the motor is suspended. Inconsequence, the opening motion of the valve is interrupted and itsaperture is fixed in the position held at that moment.

When. by reason of a water increase in the boiler, the mercury column intube E reaches contact with electrode b (which takes place when theboiler water level is slightly above the normal level) the current incoil bm is established and closes switches bi, b: and in. The break inline 2 then ends because that line i closed through switch bi; line I isplaced in contact with line 3 through switch b2, and line 2 is placed incontact with line 4 through switch D3.

The motor then receives its normal current through lines I and 2 asbefore; but it receives the starting current entering by 3 and going outby 4, that is. in inverse direction to the previous case. Inconsequence. the motor renews its motion; but this time the motion takesplace in inverse direction to the previous one, that is, it produces theslow and progressive closing of the aperture of the valve governing thewater feed.

As has been described in the third arrangement disclosed in my firstabove mentioned patent application. the construction which accomplishesthe suppression of oscillations consists in the employment, in the tubecontaining the indicating liquid, of one or several supplementaryelectrodes, outside of the electrodes a and b, whose function is tointerrupt the current when the level of the indicator liquid column,after having passed one of such electrodes in moving from the center ofits oscillations toward its extremes. and returning toward the center,passes said electrode again.

The functioning of electrode is carried out by means of coil C whichgoverns 4 switches, namely, switches 01 and b that open when the currentpasses through the coil C, and switches b" and c: that close when thecurrent passes through coil C. When the left hand end of the mercurycolumn does not reach the point b, no current whatever passes throughthe coil bm.

' As long as the mercury does not reach electrode c,

the switch 01 remains closed; and since there is no current coming fromc, that switch does not transmit any current to the coil C; while switchI) is closed and transmits the current from b to the coil bm. This coilbm governs the motor M so as to keep it going in the proper direction toslowly and progressively reduce the aperture of the valve.

When the mercury column continuing its motion toward the left comes incontact with the electrode 0, the coil C receives current through theswitch Cl and produces the opening of said switch or and of switch b,but at the same time it closes switches b" and 02. Switch b keeps up 1ecurrent in coil C, and switch 02 keeps up the current in coil bm. When,after having passed its maximum, the level in the boiler descends againand the mercury column receding toward the right loses contact withelectrode 0, the current of that electrode, which was feeding coil bmthrough switch c: i broken, and in consequence the motion of the motorgoverned by said coil bm is also suspended. The valve is then fixed atthe aperture position held by it at that moment.

This operation is based on the supposition 8thattheooiiCmaybeabletoms-keacontactat b" in spite of remaining withoutcurrent during the very short lapse of time which may pas between theopening of switch or and the closing 01' switch b". I: it werenecessary. an arrangement might be employed to guarantee these operatingconditions, having the object oi delaying the opening of the switch 01.To that end. between the plate which through its motion either opens orcloses that switch and the seat of the same, small springs areinterposed that are compressed when the switch closes and are expandedwhen it opens; the opening operation being delayed by reason of theextension oi the time or contact provided by said expansion.

The electrode it operates in precisely the same way, and so does notrequire a new description.

I have already pointed out that this system brings the position 01' thevalve that is fixed in each oscillatory motion quite near to its exactlycorrect aperture position, reducing the oscillation in that way.

Figure 3 represents the same regulation as Figure 1, even it carried outin a diflerent way. An electric current passes through the part ab oithe tube M. Said current goes also through an electromagnet E1. Thecurrent is produced by an electric source P of constant voltage. Theintensity or amperage oi the current varies with the resistance of thecircuit, and that resistance, in turn, varies as the mercury columnpenetrates into the tube M more or less from a toward b.

Another arrangement is represented in the figure, namely, theinterposition of tube D' between the variable level apparatus and theboiler. An arrangement oi this type is recommended principally for highpressure boilers having small steam and water chambers; since, when byreason of an increase in steam consumption in these boilers the pressurefalls suddenly and an instantaneous evaporation is produced, the waterstored becomes emulsified by the steam produced and its level risesconsiderably. Ii the regulating level were directly attached to theboiler, the momentary disturbance created in the boiler would have anunfavorable effect upon the regulation. The small tank D acts like aspring which avoids these difllculties, because the level variations inthe boiler are not instantly transmitted to that tank. Such levelvariations in tank D are produced by a stream or water that it receivesor transmits to the boiler through valve V; which required a substantiallapse of time.

The arrangement also prevents undesirable eifects from the diiferencesin pressure that would be momentarily produced at the point of the waterchamber of the boiler where the variable level apparatus might beattached, caused by the fact that the steam bubbles that rise throughthe water and pass that point, or near to it, produce a suction withinthe water surrounding them.

Figure 4 represents the application of the same system to the regulationof liquid fuel through diflenences in boiler pressure to maintain suchpressure constant. In said figure the pressure is indicated by acompressed air manometer A with a mercury column, connected to the steamchamber of the boiler. The regulating electric circuit comprises tubeN4. of the mercury column of the manometer from a to b and anelectromagnet S which has been shown as cylindrical in shape. Thegreater the pressure; the longer is the column of mercury in the tube Nand the smaller is the electrical resistance or the circuit. Inconsequence, the current produced by the peremeter shifting to the rightof source P runs through the circuit with greater intensity; the fixedmagnet E located adjacent oscillating armature I" on shaft (3*magnetized in the same sense repel each other with greater strength; andsuch greater repulsion moves armature I", rotating shaft G and thepinion H carried thereby meshing with rack 1 connected to the stem ofvalve V, causing the rack I to descend, thus producing a greater closingof the valve V.

Figure 7 represents an automatic regulation system which applies thearrangement that suppresses the oscillations. Said automatic regulationis intended to be accomplished through water level variations in theboiler Cu to maintain the water level constant. The

viously described with its horizontal column of mercury whose motions,reflecting the motions of the water level, modified the conductivity ofthe tube containing it, as illustrated in Fig. 3. Such change ofconductivity in the part a l; of that tube is applied to the regulation,which is accomplished as follows:

The electric current which runs through the circuit including the part aof the horizontal indicator tube, runs through an amperemeter which isso regulated that its needle stands at the center of the scale when thelevel in the boiler is normal, and deviates, for example to the left,when, th level having fallen, the mercury column occupies a smallerportion or the tube b the electrical resistance of the tube increasesand the electric current in the circuit decreases. On the contrary, whenthe level in the boiler rises above normal, the mercury column,occupying a greater portion of the tube (19b decreases the resistance ofthat tube and increases the electric current in the circuit, the needleof the amthe center of the amperemeter scale.

A second current passes through dr: and d1 into the needle or theamperemeter. when that needle is at the center 0! the scale the currenthas not outlet; but when the needle deviates to the left and makescontact with the resistance 011, that resistance conducts the currentthrough 031 to the coil B, from which it exits through lines (1, d",(12'! and 2.

As the intensity of the current of the circuit through (13123 decreases,the needle of the amperemeter shifts downward and the part of theresistance cm in the circuit of the coil B1 diminishes. In consequence,the current in that coil increases. On the contrary. when the levelrises in the boiler and by reason of that rise the column of mercurypenetrates deeper into the tube (1 b diminishing its resistance; oncethe level of the water in the boiler rises above normal, the amperemeterneedle passes into the right hand part of the scale and comes in contactwith resistance can which transmits the current of the second circuitpassing through the needle. The current of that second circuit existsthrough the lead 0" to the coil 3'1 and hence to the line 2 through thelines d" and (in.

The higher the level in the boiler the more the system uti- "lizes thelevel of several fluids and has been preor partially a bad 10 and withan intensity that goes on increasing as that level rises.

Both coils act upon two united soft iron cores 1" and I", the motions ofwhich are regulated by two springs D so that to an intensity of thecurrent, or to a given height of the boiler water level, therecorresponds a given position of both cores. These two cores carry alongin their motion an appendage K situated between them. We shall proceedto study the operation or that appendage.

We shall suppose, for example, that, the water h'aving fallen in theboiler, the resistance of the tube d b" has increased and theamperemeter needle has declined to the left, havin established thecurrent in the coil 1311. Then, the iron core I" is attracted by coilB11 and the appendage K moves to the left. The appendage K is totallyconductor of electricity; but on its right and left faces it carries twoplates F and F" of good conducting metal.

'As soon as the appendage,'iollowing the motion of the cores, movestoward the left, the plate F" comes into contact with the plate I" andre.- ceives through that second plate the current of line I throughdl'l. The motion of the appendage places plate F" rapidly in contactwith the small rod J" and in consequence starts the transmission to thatsmall rod of the electric current received by F" from the line I. Thesmall rod J" passes through the piece H" with some friction and, inturn, transmits the electric current of line i to piece H". The currentthen exits from H" by line h" to coil E" and from that to the main line2 through the lines 1", l" and dn. In that way the current isestablished in amperemeter needle shifts downward, the smallcoil E".

switches e1, ea and e; and in that way causes the passing of the normalcurrent through motor M, so as to caus that motor to rotate toward theright. Said motor actuates either the admission valve of the steamengine which drives the feed pump, or upon the rheostat of the electricmotor which drives the feed pum-p, so as to slowly and progressivelyincrease the water feed as long as the piece F" keeps contact with thesmall rod J". On the other hand, as the attraction of the core I" by thecoil 3 increases, it draws the appendage K toward the left, andappendage K draws in its motion the small rod J" which continues toslide into the interior of the piece H". In the longitudinal motion thesmall rod J" draws frame U" and the small rod J" which slides on thepiece H in the same way as the rod J" slides on the piece H".

As long as the motion of frame U" continues toward the left the currentpasses through the coil E" and the motor M acts to increase the apertureof the valve which, directly or indirectly, regulates the water feed.when such valve regulating the water feed shall have reached its properpoint and established a feed adapted perfectly to the steam consumptionoi the boiler, the descending motion of the boiler water ceases and, inconsequence, the intensity of the current in B also ceases to increase.The appendage K maintains a fixed position and ceases to draw the frameU", but it continues in contact with the small rod J", and the currentof the circuit of coil E" is maintained.

.But, since the motor continues increasing the aperture of the valveregulating the water feed, that feed rapidly assumes a slight excess inrelation to the needs of the consumption and the water level in theboiler beginsjo rise. A soon as that rise occurs, the mercury columninside the tube a'b goes on increasing slightly and the current of thecircuit through a b along with it; the needle of the amperemeter Aascends slightly, increasing the resistance C11 01' the circuit of thesolenoid B and diminishing the intensity of the current in that circuit;the coil B has less force of attraction and the iron cores are impelledtoward the right by the action of the springs D11. The appendage followsthat motion of the iron cores toward the right and loses contact withthe small rod J". As soon as that contact ceases, the current throughthe coil E is suspended; and in consequence, the motion of the motor Mis also suspended. The aperture of the valve remains invariable fromthat moment on in a position very near to its proper one.

If the level descends again thereafter, the appendage K" returns againtoward the left, the piece F" again renews its contact with the smallrod J and the current through the coil E is reestablished, that is, themotor begins again to increase the aperture of the valve. On thecontrary, if owing to a slight excess in the valve aperture or to adecrease in the steam consumption, the boiler water level rises, thecurrent passing through B1 goes on disminishing in intensity, theappendage K moves toward the right and the plate F" comes into contactwith the small rod J pushing the whole frame by means of that small rod,including the small rod J" toward the right. But since the plate F" doesnot receive at that moment any current, neither can it transmit it to .7

It is only when, the water level having passed above the normal level,the coil B comes into operation and slightly deviates the appendage Ktoward the right in relation to its normal position, that the piece Fcomes into contact with the piece F receiving from the latter thecurrent of line I through the lines d1! and f" and transmitting thecurrent to th coil E through the small rod, the piece H" and the line)1". Since that coil is connected at its-other end with line 2 throughthe lines 1 and (121, the current passes through that coil and theswitches e'1, e: and e: are closed. These switches connect the normaland starting current to the motor in such a way that the motor operatesin inverse direction to its previous motion, moving toward the left;that is, slowly and progressively diminishing the aperture of theregulating valve which governs the water feed.

From that moment on, the appendage K operates with the rod J" in thesame way as I have described in relation to its operation with the rod JThe arrangement thus fulfills the conditions that I have previouslystated, namely, that as long as the water level descend the regulationoperates by enlarging the aperture of the valve governing the feed; andwhen the level ceases to descend and starts rising, the aperture of thegoverning valve also ceases to be modified, leaving it set at an amountrepresenting very nearly its proper aperture, in accordance with thesteam consumption. When, on the contrary, the water level rises inexcess, the regulation operates to diminish the aperture of the valvegoverning the water feed; and finally, when that water level begins todescend said regulation ceases to act upon the aperture of the governingvalve, thus leaving that aperture in a position substantiallyrepresenting its proper aperture in accordance with the steamconsumption of the boiler at that moment.

The cessation oi regulation is not directed immediately at the instantthe characteristic being regulated reaches the maximum value, but at theinstant this characteristic begins to move in a reverse direction. Thereis an lndispensible time lag between the period when the characteristicto be regulated reaches a maximum value and the period when theregulation ceases. This time lag results from the inevitable delayinherent in mechanical and electrical operations. Therefore, even thoughthe train of operations necessary to effect cessation of regulation isinitiated immediately after the characteristic to be regulated reaches amaximum value, the actual cessation of the regulation takes place aftera short interval. Even assuming that when the characteristic reaches amaximum value the valve is at a proper opening for net zero flow, theregulation necessary to initiate the return of the characteristictowards normal value requires an overregulation of the valve. The slightoverregulation of the valve causes the characteristic to return to itsnormal value progressively and very slowly.

Figure 5 represents the employment of the same system applied toregulation through pressure variations instead of through variations inthe water level; but the application described graphically in thatfigure assumes that the level variations of the manometer reveal thevariations in the feed of the means of the combustion with a slightdelay, the amount of such feed being established at a volume slightly inexcess of the proper quantity when the minimum of the boiler pressure isindicated; so that in order to restore such feed to its proper level itis necessary to operate the motor in reverse direction during the shortperiod of time it may require to correct said excess of the feed of themeans oi combustion. It operates in the same way. but in reversedirection, when the manometer indicates a maximum of pressure.

The first electric circuit of the regulating system illustrated byFigure 5 comprises the manometric tube N and the amperemeter A. Saidamperemeter is so regulated that its needle is situated at the center ofthe scale when the boiler pressure is normal. When that pressuredecreases below normal the mercury drops in the manometric tube N, theresistance oi that tube increases, the intensity of the current passingthrough the circuit decreases and the amperemeter needle moves towardthe left, rising the more the greater the drop in pressure.

Said needle receives in turn, as in the preceding arrangement, a currentfrom the main line i and as soon as it starts its motion toward the leftit comes into contact with a resistance through which it transmits thatcurrent to the coil B The current exits from that coil at its other endtoward main line 2 with which such end is permanently connected.

The lower the steam pressure is, the lower is the intensity or thecurrent in the circuit which comprises the manometric tube N the greateris the needle deviation upwards, the less is the resistance interposedin the circuit of the coil 13 and the greater the current in that coil.Said coil acts upon theiron core N and in consequence its attractingaction is the greater the lower the boiler pressure falls.

When, on the contrary, the boiler pressure tube increases and creasesbelow normal, the more scribed, that desired moment and 1'3 rises inexcess. the mercury in the manometer tube N also rises in excess. Theelectric resistance oi the tube decreases below normal, the current inthe electric circuit comprising that the needle or the amperemeter Amoves from its central position toward the right, coming into contactwith a. resistance through which a circuit is established from the linei to the line 2 comprising the needle, the resistance to theright of theamperemeter and the coil B.

The current then passes through the coil 1? with greater intensity thehigher the boiler pressure rises, because as the pressure increases theamperemeter needle rises and in consequence the amount of resistanceinterposed in the circuit of the coil 13 decreases. That coil acts uponthe iron core N and in consequence acts with greater force the greaterthe increase in the boiler pressure.

The cores N and N being united and their motion regulated by the springsR and R the combined cores are attracted to the left of their normalposition when the boiler pressure decreases below normal, and are on thecontrary, attracted to the right when the boiler pressure increasesabove normal. When the pressure deit decreases, the more will the coresmove toward the left; Inversely, when the pressure rises above thenormal pressure, as that pressure goeson rising, the more said combinedcores N and N shift toward the right.

In consequence, the described part of the apparatus or Figure 5 operatesin just the same way as the similar part of the apparatus of Figure 7which has previously been described. The two cores N and N draw anappendage D situated at the center of both cores. That appendage carriestwo cross members. The lower member is formed by two rods situated onthe same horizontal plane at 180 degrees one to the other, that is, aright hand rod C and a left hand rod C Both rods pass with some trictionrespectively through the pieces F and F made of insulating material andcarrying three washers d of good electrical conducting metal.

In order to faclitate the description of the apparatus, we shall, forone moment, imagine the appendage as reduced to what has been deis, thatneither the upper cross G nor the coils E and E exist. Then as regardsthe rod C the apparatus is completed by the lower terminals a, c and theupper ones (1, b and 0 the latter being at the same level as theterminals (115, bit and Cl 5 appear to be situated in the figure.

others. The function of the washers on the pieces F and F is at the sametime the terminal as with the terminal an, the terminal be with theterminal hi5 and the terminal 05 with the terminal C15 when theappendage moves toward the left, or to place in contact the terminal awith the terminal a, the terminal I) with the terminal D and theterminal 0 with the terminal 0 when the appendage D moves toward theright.

When the first occurs, that is, the rods C and C move toward the left,the rod C draws the washers on the piece F against the correspondingterminals and thus places the terminal as in contact with the terminal(115, the terminal be with the terminal bit and b andthe terminal 05with ance with its action on the terminal 015. The normal current of themotor, assumed to be single-phase alternating, passes directly to themotor from line I,- coming out from the same through line in thterminals an and as and the line 2; and the starting current enters themotor from line I through the terminals bu and from the same by line 4and the terminals C15 and C5 to line 2. We shall suppose that thosecurrents cause the motor to revolve toward the left, so as to'operatethe valve governing the feed of the means of combustion in the directionto increase its aperture.

If, on the contrary, the rods move toward the right, the rod C placesthe terminal a" in contact with the terminal a, the terminal 17 with theterminal I) and the terminal 0 with the terminal 0. Then the normalcurrent of the motor enters the same directly by line I, and exits byline 2m, terminals a and a to line 2. The starting current enters by theline I, terminals c and c and line 4, and exits by line 3 the terminalsb and 12, line 2m and terminals a" and a to line 2. Then the motorrotates to the right, acting upon the valve governing the means ofcombustion so as sively diminish its aperture.

These features having been established, let us see how the apparatus inthe form pointed out would operate.

If we suppose, for example, that with the feed 0! the means ofcombustion perfectly regulated a decrease of pressure be producedthrough an increase in steam consumption, the coil B will come intoaction, attracting the core N and producing the motion toward the leftof the appendage D which draws the rod C That rod in turn will draw thepiece F until it contacts terminal as with terminal an, terminal be withterminal bit and terminal cs with terminal C15. The motor R will thencomeinto action so as to slowly and progressively increase the feed ofthe means of combustion of the boiler.

As long as the drop of pressure is manifest the rod will continue tomove toward the left and keep the designated contacts respectivelybetween the terminals at, be and C5 and (115, I715 and cit; that is, themotion of the motor will continue and the valve governing the feed ofthe means of combustion will open more and more. As soon as thepressureceases to drop and tends to rise, the force of attraction of thecoil B will decrease, the core N being less attracted will move slightlyto the right under the action of the spring R the appendage D willreverse its motion and will separate the washers d from the terminalsas, be, ca, (145, 1745 and 045.

The contact between those terminals will then cease to exist and themotion or the motor will be suspended, the aperture of the valvegoverning the means of combustion being in consequence fixed at anamount very near to that of its proper position in accordance with theexisting steam consumption.

It the pressure goes on increasing, the appendage D will continue itsmotion toward the right and will draw the piece F only for a short time;because the screw T the position of which can be regulated, will limitsuch action and will in consequence maintain the washers of that pieceslightly spaced from the corresponding terminals. The rod C will operatewith the piece F in the way described for the rod C in accordthe pieceF, opening and his and the line 3, coming out to slowly and progress- 15closing the electric contacts that govern the motion of the motor Rtoward the left.

The installation in that form would have a defect. If'we suppose thatunder the effect of an excess 01' pressure the appendag D has been drawnsubstantially toward the right and is returning from the right end orits path to its normal position, then during that return motion the rodwould draw the piece 1 and would place the terminals as, be and Cr incontact with the terminals 015, bra and on with the boiler pressurestill standing too high, producing rotation of the motor in thedirection to increase the means of combustion in spite of the excesswhich those means of combustion would already be exhibiting.

In order to prevent that danger it is necessary that the terminals as,be and or do not come in contact with the terminals are, bra and cmexcept when the boiler pressure is lower than normal; and in the sameway, that the terminals a, b and 0 do not come in contact with theterminals a, b and 0 except when the boiler pressure is above the normalpressure. These conditions are obtained by means of the arrangementshown in the drawing, which I now proceed to explain.

The terminals dis, bu and cu are fixed upon a plate P, capable of movingvertically under the action or a coil E, and in the same way theterminals a, b and c are fixed upon another plate P capable of movingvertically under the action of a second coil 151*. When the currentpasses through the coil E the plate P is attracted and the terminals04:, his and cu are raised in such a way that they cannot make contactwith the washers d. The coil E can raise the terminals a, b and c andtheir plate P" in the same way, and the figure shows these terminals andplate in that raised position.

The upper cross member 01' the appendage D has two symmetrical curves (3and G. When with the plate P raised, as in the figure, the appendage Dmoves toward the right, the curve G serves as a guide to the roller 0 onplate P causing the descent of the plate P until, 0 having passed underthe right arm 01' the upper cross member of the appendage D, the plate Pand the terminal a, b and c occupy their lower position. In the same waythe curve G operates with the roller 0, the plate P carrying saidroller, and terminals G15, hi5 and C- Let us suppose that with theterminals a, b and c in their upper positions, as the figure shows,owing to the passing of the current through the coil E the pressurerises in the manometer and the appendage D moves toward the right underthe action or the coil B The curve 0", advancing, will act upon theroller 0 and will cause the descent of the plate P so as to place theterminals a, b and c in their operating position. In the same way thecurve G will operate with the roller 0, at the start of a fall ofpressure. so as to place the terminals a, b and c in their operatingposition in spite of the fact that the current is passing in the coil E.In consequence; by means of the described arrangement the coils E and Ecan operate constantly upon the plates P, P without harm to theoperation, because the appendage D will compel said plates to take theiroperating positions at the time when their act is necessary.

The figure must be taken only as schematic, because not all themechanism that facilitate the motions pointe out have been shown in the16 same, such as constructing the upper terminals or the washers with abevel at their planes of contact, and also not only upon one roller forlowering the plates P and P", but upon several rollers, so that thatmotion will be eflected without friction, P and P" maintaining theirhorizontal positions during that motion. These details have not beenshown in order to avoid complications in the figure.

At the beginning of the description I have pointed out that theregulation shown by the figure under consideration permits, when thepressure had passed through a minimum the corrections automatically ofthe excess of aperture which the valve governing the feed beingregulated might have at that moment; to which end the motor wouldoperate durin a short time in reverse direction to its previous motion;and inversely, when the pressure had passed through a maximum, theexcess of the closing or the governing valve might be correctedautomatically, to which end the motor would operate during a short timein reverse direction to that of its previous motion.

The means for obtaining these desiderate consist in the employment ofthe arrangements described, by means of which the upper terminals can beraised and placed out of contact with the das long as the pressureconditions exi t n in the boiler do not require their action. I havenoted that if, for example, the appendage D, having moved toward theright owing to an excess of pressure, should return toward its normalposition, appendage D would draw the piece F" in that motion untilthe-washers d of that piece struck the terminalsaa, be and 0:; and if atthat moment the terminals an, bin and on should be at their operatingposition, namely in their lower position, they would also come incontact with the washers, the currents that are established by theclosing oi the contact through the washers d of theterminals as and an,be and bu and cs and cm respectively, would be produced; that is, themotor would again revolve in reverse direction to its previous motion.

In consequence, ii we wish rotation opposite to the preceding rotationto take place in the motor for a short time, it is sufilcient tomaintain the terminals (115, bit and C15 in their operating positionduring that short time, and, once that time has passed, to lift theplate P by meansof the coil E. That is, we have to leave the coil Ewithout current from the moment in which the appendage D shall havearrived at the end of its course toward the right, during the short timethat may be required for the motor to make the aperture correction inthe governing valve, and that time having passed, to reestablish thecurrent in the coil. The arrangement which produces these resultsautomatically is the following one.

The motor R drives screw K by means of the cogs P and Q. The motion ofscrew K produces in turn the lateral motion from right to left, and viceversa, of the piece J threaded has a central part 0 at its upper partforming a guide which slides on the interior or the upper part of theframe 5. Said'part O carries on its right and left two plates ormetallic terminals electrically insulated from said piece and inelectric connection with the line I. For this purpose I and I" areprovided independent from the piece J but shifted by its motion. Each ofsaid pieces carries on the face fronting the part 0 piece .1, a.metallic plate or terminal electrically insulatedfrom the piece carryingit, that is, the terminal 6 carried by the piece I and the terminal ecarried by the piece I. The lower partsof the pieces I and I slideduring the lateral motion of said pieces on the interior of the lowerpart of the frame 5 forming a guide I for said pieces.

The terminal of the piece I is electrically connected with the windingof coil 151 by the line (2 and the other end, of that coil ispermanently connected to the main line 2, though such connection has notbeen shown in order to simplify the figure. In the same way the terminale carried by the piece I is electrically connected with the beginning ofthe coil E by the line e", and the end of the coil E is also permanentlyconnected with line 2, even though such connection has not been shown inthe figure;

Let us see now how this part of the apparatus operates. When the motorrotates screw K toward the left in piece by the part 0 of piece J towardthe right, and the contact between the two plates carried by these twopieces and situated between them is established. Thus, the coil E isenergized and has a tendency to raise the plate P; but since the boilerpressure stands then above its normal level the appendage D is movedtoward the right, and through the roller 0 maintains plate F and theterminals a, b and c in their lower position, permitting the current topass through the motor, impelling it to revolve to the right.

In that motion the motor keeps gradually closing the valve regulatingthe means of combustion. A few moments after that valve reaches itsproper aperture for the existing steam consumption, the boiler pressurepasses through a maximum and tends to fall. The coil B acts upon N withless force of attraction and the combination of the two cores N and Nand the appendage D start their return toward the left. By reason ofthat motion the washers (Z are separated from the terminals a, b, c, a band e and the electrical contacts between a and a, b and b and c and 0that insured the passing of the operating currents of the motor becomeopen, causing the stopping of the motor. At that moment the pieces J andI are at the right hand end of their motion, the piece I being shiftedby the part 0 of the piece J through the contact between thecorresponding terminals.

The coil E continues therefore to be provided with current. On thecontrary, since the piece I removed by the screw L remains slightlyseparated from the piece 0 the terminal e is separated from thecorresponding terminal situated upon the part 0 of the piece J and thecurrent in the coil E is broken. The plate P is therefore at its lowerposition, and the terminals 1115,1215 and 015 are in operatingcondition.

The appendage D continuing its motion toward the left, the rod C -willin a very short time place the washers d of the piece F in contact withthe terminals as and 1115, ha and D15 and cs and C15, reestablishing theoperating currents of the motor to the left. The motor then resumes itsmotion in a contrary direction to its previous motion. As soon as thatmotion is started, the piece J begins to return toward the left,departing from the piece I and approaching the piece 1 The terminal eloses contact with the corresponding terminal carried by the J the pieceI is shifted with the piece I. the

part 0 of the piece J and the current in the coil E is suspended. Whenby its motion toward the left I piece J comes in contact terminal emakes contact with the corresponding terminal situated on the part 0 ofthe piece J, the current of the'line I enters the coil E through thelines I and e, and that bobbing getting into action lifts the plate Pand in consequence suspends the current operating the motor R thuscausing the stopping of that motor.

There has thus been obtained a motion of the motor in reverse direction,while the part 0 of the piece J passes from its contact with the piece Ito contact with the piece 1. The lapse of time can be regulated by meansof the set screws L and L so that the reverse movement of the motorexactly corresponds to compensating for the excess of closure that thegoverning valve showed when the maximum pressure was indicated in themanometer.

The apparatus operates in a similar way when a minimum of pressure isindicated, and therefore it is unnecessary to described that operation.

Figure 6 represents the details of one of the plates P in sideelevation.

From comparison of the systems of Figures 5 and '7, it appears that inthe first of these figures not only has the regulating process beensupplemented by an arrangement which, after a maximum in pressure orwater level in the boiler has been recorded, a slight motion of themotor inverse to its previous motion is produced to correct theimperfect aperture of the valve governing the feed regulated by theapparatus; but in Figure 5 the employment of the current which in Figure'l operated the coils E and E" is avoided, because the opening orclosing of the three contacts that renew, or suspend, the current in themotor which acts upon the aperture of the valve is effected directly inFigure 5; and, on the contrary, is effected indirectly by acomplementary current in Figure 7.

This simplification in the construction of Figure 5 has itsdisadvantages, because since the opening and closing of the threecontacts are effected by one single mechanical motion, that arrangementrequires much greater perfection in construction.

Som elasticity might be given to the terminals to prevent the contact ofsome one of the terminals from closing; but evidently the arrangement ofFigure 7, even though it requires a supplementary current, offersgreater certainty of good functioning.

This arrangement can of course be applied to Figure 5. It is sufficienttoreduce each group of terminals as, b5, ca; 11 I2 0 an, 1715, on; a, b,e to one single terminal and to apply the supplementary current in theway shown in Figure 7 to govern the motor with that single terminal, toobtain in Figure 5 the advantages of employing one single terminal.

The arrangement of Figure 5 for obtaining automatically a slight reversemotion of the motor, after the pressure of the indicated level haspassed through a maximum or a minimum, is also evidently applicable toFigure 7. In that application it will be advantageous for the coilsoperating like the coils E and E of Figure 5, instead of modifying thelocation of the upper terminals, shall open or close switches in thecircuits of the complementary currents that operate 19 ruption of suchcurrents, instead of interrupting them by displacement of the upperterminals.

Figure 8 represents an arrangement with a similar operation to that ofFigure 7, and does not have the arrangement which permits motion of themotor in reverse direction to its previous motion, after the pressure orthe level through the variations of which the regulation is establishedhas passed one of its extremes. In Figure 8 the current of the circuitab" of Figure 7 which passes through the coil 13' magnetizes the piecesA and A", producing a repulsion between these two pieces that is evergreater as the current passing through 3' is greater. Since thatrepulsion is counterbalanced by the weight of the piece A", therecorresponds to a given current a position of that piece.

Let us suppose, for example, that said apparatus is applied to regulatethe water feed by the level variation in the boiler. When that levelstands at its normal position, and the current passing through the tube(1 b of Figure 7 has its mean value, the bar J will be vertical and thepiece L at its mean position. Then plate P (see Fig. 8) as well as plateP" are lifted by springs (not shown), and this prevents all theterminals from coming into contact.

When the boiler level falls and, in consequence, the current passingthroughthe tube a l) of Figure 5 decreases, the piece A" approaches thepiece A, the appendage K moves toward the left and the piece L', actingthrough its curve G' upon the roller causes the plate P to descend,allowing the washers of the piece F to place the terminals of the plateP in contact with the terminals as, be, and 05, so that through suchcontacts the motor is started. But, at the same moment, the plate Pbeing lifted, the terminals of that piece cannot receive current throughthe washers of the piece F and, in consequence, cannot intervene in themotion of the motor.

When, on the contrary, the boiler level rises above normal and, inconsequence, the current of the electric circuit a b" increases abovethe mean current, the piece A and the piece A" repelling each other withgreater force, A gets farther from A", the bar J inclines toward theright and acts through the roller 0 upon the plate P to maintain theterminals of that plate in a position permitting them to receive, and totransmit to the motor the currents that cause the motion of that motor.In consequence, by virtue of that arrangement, as long as the level islower than normal only the terminals of the rod C may act, and on thecontrary, when the level is higher than normal only the terminals of therod C may act.

This flgure has been arranged for three terminals in each group, as inFigure 5; but it might also have been limited to one single terminal asin Figure '7, as has been previously explained.

I claim:

1. An automatic regulating system for steam boiler systems comprising acoil formed of vertical tubes and arranged with one end of the coilconnected to the steam zone in the boiler, non-miscible liquids ofdifferent densities fllling said tubes, the upper ends of two adjacenttubes being connected by a horizontal tube of reduced diameter, one ofthe liquids being a column of mercury located in the horizontal tube.the arrangement being such that the mercury column is shifted bymovements of the liquids in the coil in accordance with variations in anoperating characteristic of the boiler, and said liquids are maintainedin equilibrium by variations in the proportion of light and heavy liquidin each tube when said liquids are shifted, counterbslancing liquidcontacting the ends of the mercury column being poor conductors ofelectricity, means for adjusting a fluid feed to the boiler system, andelectrical control means for the adjusting means connected to saidmercury column and actuated by movement thereof, arranged to vary saidfeed in accordance with variations in the position of said mercurycolumn corresponding to variations in said operating characteristic.

2. Apparatus as set forth in claim 1 in which the fluid feed comprisesthe supply of water to the boiler.

3. Apparatus as set forth in claim 1 in which the fluid feed comprisesthe feed of an element of combustion to the boiler system.

4. Apparatus as set forth in claim 1 in which the electrical controlmeans includes two spaced electrodes in the path of the mercury columnarranged to be bridged by said column when shifted from normal position,and a control circuit connected across said electrodes 5. Apparatus asset forth in claim 1 in which the electrical in series therewith, alongwhich the mercury travels to vary the effective resistance of theconductor, and a control circuit including said mercury column andconductor in series.

6. A regulating system for correcting variations in a givencharacteristic from a constant, including an apertured devicecontrolling the value of the characteristic, control means for changingsaid aperture automatically when said characteristic varies from itsconstant in a direction appropriate to correct said variation, includingan electromagnet, an armature shifted by said electromagnet whenenergized and a control member shifted by the armature during correctivemovement of the latter, electrically operated means for varying saidaperture and an electrical control system for the latter means,including an actuating circuit passing through the contact between thearmature and said control member, the arrangement being such that whenthe movement of thearmature is arrested and reversed by completion ofthe correction, the armature and control member will separate, breakingthe contact and deenergizing the actuating means.

7. A regulating system for correcting variations in a givencharacteristic from a constant, comprising a regulating device forvarying said characteristic, means including a motor for operating theregulatin device and an electrical control system for the motor,including an electromagnet, electrical means for varying the currentthrough the electromagnet in accordance with variations in saidcharacteristic, an armature associated with the electromagnet andshifted in accordance with variations in said current, and a movablecontact element shifted by engagement with the armature during movementthereof away from mean position corresponding to the constant of saidcharacteristic, the motor circuit passing through the contact betweenthe armature and the movabl member, the arrangement being such that thearmature is shifted away from the movable member, opening the motorcircuit and arresting the corrective movement of the valve, when thearmature reverses its direction of movement toward its mean position.

8. A system as set forth in claim '1, including a spring member locatedat the contact between said armature and movable member and compressedby the corrective movement of the armature, arranged to maintain saidcontact during decompression of the spring during a limited period atthe beginning of the returnmovement of the armature.

9. In a steam boiler regulating system apparatus controlled inaccordance with variation in a condition in the boiler to vary a feed tothe boiler system comprising an electric circuit in which a resistanceis interposed varying at the same time as the operating characteristicand an amperemeter; amperemeter needle and a resistance the amount ofwhich interposed in the circuit varies with the position or theneedle'on its scale, that second circuit comprising an electromagnetwhich draws along an appendage, a third electric circuit including amotor controlling the feed to said boiler, the normal position of saidappendage corresponding with the normal value of the regulatingcharacteristic, said appendage on deviating from that normal position topredetermined extreme positions under the action of a current variationin the electromagnet closing said third electric circuit to causeactuation of said motor and thereby modify said feed in a compensatingdirection in accordance with the direction of deviation of theregulating characteristic at that moment.

10. A steam boiler regulating apparatus as set a second circuitcomprising thependage during movement from normal position, acooperating contact elementslidably mounted on the rod, said contactelements being connected in said electrical circuit system, and a stoparranged to arrest the slidable contact element in suitably spacedrelation to the fixed contact element during return movement of theappendage.

14. A steam boiler regulating apparatus as set forth in claim 9 in whichthe third electrical circuit includes two component circuits, one closedwhen the regulating characteristic is greater than its normal value andthe other closed when said regulating characteristic is less than thenormal value, and in which the appendage is provided with two rods andmeans is provided for shifting the first rod when said characteristic isgreater, and shifting the said second rod when said characteristic isless, than its normal value, said shiftforth in claim 9 in which thethird electric circuit includes two component circuits, one closed whenthe regulating characteristic is greater than its normal value and theother closed whensaid regulating characteristic is less than the normalamount, and in which the appendage is provided with two rods, the firstone shifted when the regulating characteristic is greater than itsnormal value and the second one when the regulating characteristic isless than its normal value.

11. A steam boiler system regulating apparatus comprising a device forvarying'a feed to the boiler system, mechanism including a motor foroperating the device to vary saidieed means and a motor control systemincluding an electromagnet, means for varying the current through theelectromagnet in accordance with deviation in said characteristic fromnormal, an armature associated with the electromagnet and shifted inaccordance with variations in said current, a movable rod engaged andshifted by the armature during movement from normal position, a motorenergizing circuit including a fixed terminal, and a terminal movablymounted on the rod arranged to contact the fixed terminal when the rodis shifted from normal position and movable on the rod while maintainingsaid contact during continued movement of the rod in the same direction,the arrangement being such that when the deviation is compensated andthe armature and rod commence movement in the reverse direction towardnormal position, the contacts will be separated and the motor circuitbroken.

12. Regulating apparatus as set forth in claim for shifting the movablecontact in the reverse direction on the rod during reverse movement ofthe rod toward normal position while maintaining said movable contactspaced from the fixed contact.

13. A steam boiler regulating apparatus as set forth in claim 9including a fixed contact element, a movable rod engaged and shifted bythe ap- 11, including means ing means including a lost motion connectionwhereby an interval is provided between the end of the operativemovement of one rod and the commencement of the return movement of theother rod.

15. A steam boiler system regulating apparatus including means foradjusting a feed to the boiler system and electrical means forautomatically operating the adjusting means to correct variations fromnormal in a characteristic of the boiler system, including an electricmotor, and an electrical circuit system for controlling the operation ofthe motor including two contact rods, cooperating fixed contacts, meansoperable upon deviation of said characteristic in one direction formoving one rod to close its corresponding contact and energize the motorfor operation in one direction, means operable upon deviation 01' saidcharacteristic in the other direction for shifting the other rod andclosing appropriate contacts to actuate the motor in the oppositedirection, control switches in the circuits of the contacts carried bysaid rods, and electrical means for closing said switches selectively toenergize the proper contacts.

16. A process for regulating a steam boiler in accordance with thevariations in one of the operating characteristics of said boiler, tomaintain said characteristic at a predetermined normal value, whichcomprises effecting continuous regulation of said characteristic in adirection tending to restore said characteristic towards normal value assaid characteristic departs from said normal value, effecting a slightcounter-regulation in an opposite direction ceases to depart from saidnormal value and approaches said normal value to compensate for anexcess correction effected in said characteristic by said regulation inits original direction, and thereafter maintaining said regulationcontinuously arrested while said characteristic is approaching saidnormal value.

17. An apparatus for automatically regulating a steam boiler inaccordance with variations in one of the operating characteristics orsaid boiler, to maintain said characteristic at a. predetermined normalvalue, comprising means for effecting continuous regulation of saidcharacteristic in a direction tending to restore said characteristictowards normal value as said characteristic departs from said normalvalue, and means for eflecting a slight counter-regulation in anopposite direction when said characteristic ceases to depart from saidnormal value and approaches said normal value to compensate for anexcess correction eflected in said characteristic by said regulation inits original direction, and ior thereafter conwhen said characteristicflnuouely meintelmnz said recuhflon arrested while aid charactemtlc isapproaching and nor- JEAN LOUMET n LAVIGNE.

REFERENCES CITED The following references are of record in the me 01this patent: I

UNITED STATES PATENTS Number Number Name Deflc Andenon 6t 11. Feb. 22,1921 McNeil] Jim. 15, 1929 Gil-D0110 Dec. 20, 1932 Btender Nov, 17, 1931Harvey Mar, 13, 1923 Dickey Aug. 22, 1939 Stein May 31, 1933 KimballNOV. 25, 1930 Eddy Oct. 9, 1940 FOREIGN PATENTS Country Date France Oct.2, 1933 Great Britain July 31, 1928 GeImQ-ILV June 30, 1924 France -1-Jan. 23, 1932

